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Subject: Re: Endgame: Best Move and Tuning

Author: Dann Corbit

Date: 13:54:21 03/04/06

Go up one level in this thread


On March 04, 2006 at 16:48:33, Dann Corbit wrote:

>On March 04, 2006 at 16:30:09, Charles Roberson wrote:
>
>>
>>
>>    Telepath drew a won endgame in a blitz match this week. The position is:
>>     8/8/8/5BB1/8/3p1kpp/7P/7K w - - 0 76
>>
>>    It only searched 6 ply and played Bxh3.

OOPS!!  I thought your program played Bxd3.  Bxh3 is just awful.  Bxd3 wins
also, but hxg3 is the clear choice here.  If he tries to push the pawn towards
queen by backing with his king, you cough up a bishop for a queen.  And if he
takes it with his king, you clear off all of his pawns easily and do the
diagonal bishop dance for an easy win.

>>    At 10 ply it played Bxd3.
>>
>>    Seems to me the better move is Bxd3 or h2xg3.
>>    I've tried upping the outside passer value by 4x and adjusting
>>     the code to call the d3 pawn an outside passer. Now, it makes
>>     Bxd3 at 9 ply and h2xg3 at 10 ply then Bxd3 at 11 ply.
>>
>>    Seems I should be able to adjust it to see this earlier or would
>>    that be overtuning?
>
>Rybka likes Kg1 (which wins, but is a very puzzling choice because hxg3
>obviously wins very easily.)  Considering Rybka's long struggle to get off of
>the drawing Bxd3 I would not be too worried about it if my program struggled
>with it a while also.  However, a 6 ply depth is a great concern if your program
>has more than one second of think time.  Why so shallow?  Severe time pressure?
>
>Analysis from e:\ttt.epd
>3/4/2006 1:34:36 PM Level: 999 Seconds
>Analyzing engine: Rybka v1.01 Preview 2.w32
>
>1) 0 76
>    Avoid move:
>    Best move (Rybka v1.01 Preview 2.w32): Kh1-g1
>    Not found in: 16:39
>      3	00:00	       5.744	74.453	+6.63	Bf5xd3
>      4	00:00	       7.300	78.686	+6.95	Bf5xd3
>      5	00:00	       8.974	82.787	+5.80	Bf5xd3 Kf3g4
>      6	00:00	      11.816	109.005	+6.69	Bf5xd3 Kf3g4 Bg5c1
>      7	00:00	       7.248	58.904	+6.69	Bf5xd3 Kf3g4 Bg5c1 g3g2+ Kh1g1 Kg4h5
>      8	00:00	      19.898	107.807	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5
>      9	00:00	      40.591	155.674	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5
>     10	00:00	      80.591	187.984	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3
>     11	00:00	     150.801	209.810	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4
>     12	00:01	     265.335	225.666	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6
>     13	00:02	     444.369	236.627	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5
>     14	00:03	     712.987	244.507	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     15	00:05	   1.105.819	250.688	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     16	00:06	   1.662.474	255.113	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     17	00:09	   2.448.383	257.936	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     18	00:14	   3.549.358	258.999	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     19	00:20	   4.997.370	260.741	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     20	00:27	   6.939.724	260.618	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     21	00:37	   9.331.828	261.008	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     22	00:50	  12.634.594	261.032	+6.75	Bf5xd3 Kf3g4 Bg5c1 g3xh2 Kh1xh2 Kg4h4
>Bd3f5 Kh4h5 Bf5xh3 Kh5h4 Bh3e6 Kh4h5 Be6f5 Kh5h4
>     22	02:25	  34.944.570	247.097	+16.60	Kh1g1 d3d2 Bg5xd2 Kf3e2 Bd2g5 Ke2f3
>Bg5c1 g3g2 Bf5xh3 Kf3e2 Bh3xg2 Ke2d1 Bc1e3 Kd1c2
>     23	02:44	  39.836.036	247.997	+16.66	Kh1g1 d3d2 Bg5xd2 Kf3e2 Bd2g5 Ke2f3
>Bg5c1 g3g2 Bf5xh3 Kf3e2 Bh3xg2 Ke2d1 Bc1e3 Kd1c2
>     24	05:03	  71.486.462	241.254	+M75	Kh1g1 d3d2 Bg5xd2 Kf3e2 Bd2g5 Ke2f3
>Bg5c1 g3g2 Bf5xh3 Kf3e4 Bh3xg2+ Ke4f5 Bg2f3 Kf5g6
>   3/4/2006 1:43:36 PM, Time for this analysis: 00:08:56, Rated time: 16:39
>
>0 of 1 matching moves
>3/4/2006 1:43:36 PM, Total time: 12:08:59 AM
>Rated time: 16:39 = 999 Seconds



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